Robot with suction cup attachment to steam generator partition

ABSTRACT

A robot for carrying out operations in, for example, a chamber of a heat exchanger being divided into two compartments by means of a partition can be attached to said partition by means of suction cups. An accurate vertical movement of the shoulder joint necessitates the application of either two hinges or a double hinge between the robot itself and the suction cups.

The invention relates to a robot that is particularly, yet notexclusively, suitable for being hoisted into one of the chambers of aheat exchanger being separated from one another by a partition, in orderto carry out inspection and repair work.

Dutch Patent Application 88 01431 is one of the documents disclosing arobot for carrying out operations in a heat exchanger, comprising asupporting means including two guide shafts along which a table isreciprocable, a shoulder joint arranged on the table to rotate amounting head about a vertical axis, a forearm being pivotably connectedto the mounting head and having an elbow joint at its other extremitywhich supports an upper table along which an upper arm is reciprocable,said upper arm being capable of carrying inspection or reparation toolsat one of its extremities, and driving means for the lower table, themounting head, the lower arm, the elbow joint, and the upper arm.

One feature of the known robots of this type is that the supportingmeans comprises i.a. a pair of pins that are to be fixed into the tubeplate of the heat exchanger. As a result, neither of the tubes occupiedby said pins can be examined in a simple manner, for example, by using atelevision camera, as is usual.

The invention aims to provide a solution to this problem. To this end,the supporting means according to the invention comprises a table plateincluding guide shafts for the lower table, and a base plate onto whichsuction cups are applied to attach the robot to a wall, the partition ofa heat exchanger in particular.

The table plate and the base plate are preferably connected to oneanother by means of a double hinge, so as to enable an accuratepositioning of the table plate in the planes parallel and perpendicularto the tubes of the heat exchanger.

The forearm may consist of two parallel parallelogram arms which are, attheir ends facing away from the mounting head, linked together in apivotable manner, about coupling pins, by means of a coupling arm whichis pivoted about a horizontal pivot pin to a supporting plate of theelbow joint. Preferably, the stop surfaces of the coupling arm areorientated in such a manner that the upper arm is in horizontal positionwhen in operation. The stop surfaces may be of a cranked design.

The upper arm and/or the wrist joint may be provided with means forsecuring the upper arm in hoisting position either onto one of theparallelogram arms and/or the mounting head.

The invention will be discussed below in more detail with reference tothe drawings showing, by way of example, an embodiment of a robotaccording to the invention. In the drawings:

FIG. 1 shows a perspective view of a model of the robot with the lowertable in the lowest position and the upper arm being folded down on theforearm,

FIG. 2 shows a schematic side view of the robot with the lower table inthe highest position and the upper arm in horizontal position,

FIG. 3 shows a schematic view of a possible way of setting the positionof the table plate in relation to that of the base plate in the plane ofthe drawing of FIG. 2 and in a direction perpendicular to either plate,and

FIG. 4 shows a schematic view of a possible way of setting the positionof the table plate in relation to that of the base plate in a plane thatis substantially parallel to either plate.

As FIG. 1 is based on a demonstration model, it shows two out of threelegs serving to support the model on a table.

When comparing FIGS. 1 and 2, one notices that some passages of theelongated members 12 and 13 extend just between other surface pairs.These passages are provided primarily for reasons of saving weight, andtherefore, their exact arrangement is of minor importance. Besides,member 6 may be provided with passages as well for the very same reason.

The invented robot is particularly suitable for being used in one of thechambers of a non-depicted heat exchanger, the chambers being separatedby a partition 1. This partition 1 has a surface which is shown in FIG.2 as being smooth and straight, though this may be different in actualpractice. The robot comprises a base plate 2 having, on its surfacefacing the partition 1, two vertical rows (one of which is representedin the drawing) of a variable number of suction cups 3 which areconnected to a vacuum pipe 4. If the surface of the partition 1 isuneven in formation, the shape of the base plate 2 is conformed to it.The base plate 2 is connected to a table plate 6 by means of a doublehinge 5. The double hinge or universal (so-called `cardan`) hinge 5 canbe operated by means of two (non-depicted) controllable motors, one foreach hinge movement, so as to be set to the required position. Thehinges of the double hinge 5 enable a hinge movement about two mutuallyperpendicular, horizontal axes. In this way the table plate can belevelled and positioned as well as maintained in planes exactly paralleland perpendicular to the partition 1 and the tube plate.

FIGS. 3 and 4 show a schematic view of a possible way of setting theposition of table plate 6 in relation to that of base plate 2 in avertical plane perpendicular to the base plate 2, in case the base plateis positioned substantially upright. For this purpose, the table plate 6is provided with a passage 34 being provided with an inner thread andextending through said table plate 6. The base plate 2 is provided witha threaded spindle 35, the extremity 36 of which is accomodated in anon-threaded sleeve 39 so as to be rotatable about its longitudinalaxis, said non-threaded sleeve 39 being pivoted into the base plate 2,thus enabling the threaded spindle 36 to conform to the orientation ofthe passage 34. By providing means which are not depicted for reasons ofclarity, such as a motor serving the purpose which engages the otherextremity of the spindle 36, so as to impart rotary motion to it, aswell as operating means for said motor, the spindle 36 is rotated aboutits longitudinal axis, whereby the position of the passage 34 on thespindle 35 is changed, and the table plate 6 is rotated around the fixedpoint of rotating, constituted by hinge 5, about an axis A--Aperpendicular to the plane of the drawing, thus being relativelyinclined in relation to the base plate 2.

The front side of table plate 6, that is the side of the table plate 6facing away from the base plate 2, includes a thin, circular rotary disc37 provided with an eccentrically positioned hole into which a pen 38projects which is pivotably and slidably, in a reciprocable manner, asviewed in the plane of the drawing of FIG. 3, mounted to the base plate2.

By providing means which are not depicted for reasons of clarity, suchas a suitable so-called `pancake` motor, and operation means pertainingto it, the edge of the disc 37 can be engaged, so as to impart a rotarymovement to disc 37 about the pin 38. Due to the eccentric bearing ofthe disc 37 on pin 38 the table plate 6 will be forced to rotate at thefixed point of rotation 5, constituted by hinge 5, about axis B--B, thusbeing relatively inclined in relation to base plate 2.

The table plate 6 supports two guide shafts 7 along which a lower table8 is movable up and down by means of a threaded spindle being arrangedbetween the axes 7 and driven by a motor 9. Onto the lower side of thelower table 8 a shoulder joint 10 is applied which is capable ofrotating about a vertical axis in co-operation with a mounting head 11arranged on the upper side of the lower table 8.

The mounting head 11 supports a forearm constituted by two parallelogramarms 12, 13 with the aid of pins 14, 15. At their ends facing away fromthe mounting head 11, these parallelogram arms 12, 13 are linkedtogether in a pivotable manner, about pins 16, 17, by means of acoupling arm 18.

Between the parallelogram arms 12 and 13 a motor 19 including threadedspindle 20 is arranged, so as to impart an up-and-down motion to thearms 12, 13. The motor is fed through a feed cable 21.

The coupling arm 18 has an enlarged upper part for accomodating a hingepin 22 for a supporting plate 23 of an elbow joint 24 that is arrangedbelow an upper table 25. The stop surfaces 26 are orientated in such amanner that the upper table 25 and--as a result--an upper arm 27supported slidably on it, are positioned horizontally. The stop surfaces26 as shown in FIG. 2 are of a cranked design. The drive of the upperarm 27 comprises a motor 28 including a threaded spindle which isarranged between the two guide shafts 29.

On the upper arm 27, at the end facing away from the motor 28, a wristjoint 30 has been arranged, onto which the (non-depicted) inspection andrepair tools may be applied. The wrist joint 30 includes a motor that isfed by a feed cable 31. Additional feed cables are schematicallyindicated by reference numerals 32 and 33.

Along with the lower table 8 the parts 11-32 may be folded in theformer's lower position in such a manner that the entire robot has meredimensions of circa 110×25×25 cm. Such a robot is relatively simply tobe hoisted through a manhole of a heat exchanger, provided that in oneof the holes of the tube plate a hoisting eye has been temporarilyarranged.

The scope of the claims also include other embodiments than the onerepresented in the drawings.

I claim:
 1. A robot particularly suitable for being hoisted into one ofthe chambers of a heat exchanger steam generator, said chambers beingseparated from one another by a partition, so as to carry out inspectionand repair operations, comprising a supporting means including guidemeans along which a first table is reciprocal, a shoulder joint arrangedon the table to rotate a mounting head for a robot arm assembly about avertical axis, as well as driving means for said first table, saidmounting head, and said robot arm assembly, said supporting meanscomprises a table plate (6) on which said guide means (7) for said firsttable (8) are provided and a base plate (2) onto which suction cups (3)are applied to secure the robot to the partition (1) of the heatexchanger.
 2. A robot according to claim 1, wherein the table plate (6)and the base plate (2) are connected to each other by means of a doublehinge (5), in order to enable an accurate positioning of the table plate(6) in the planes parallel and perpendicular to the partition (1) andtube plate of the heat exchanger.
 3. A robot according to claim 1,wherein the robot arm assembly comprises a forearm (12, 13) beingpivotably connected to the mounting head (11) and having an elbow jointat its other extremity which supports a second table (25) along which anupper arm (27) is reciprocable, said upper arm being provided with awrist joint (30) at one of its extremities including means for carryingtools.
 4. A robot according to claim 3, wherein the forearm comprisestwo parallel parallelogram arms (12, 13) which are, at their ends (11)facing away from the mounting head, linked together in a pivotablemanner, about coupling pins, (16, 17), by means of a coupling arm (18)which is pivoted on a horizontal pivot pin (22) to a supporting plate(23) of the elbow joint (24).
 5. A robot according to claim 4, whereinthe orientation of the stop surfaces (26) of the coupling arm (18) andthe supporting plate (23) is such that the upper arm (27) is inhorizontal position.
 6. A robot according to claim 5, wherein the stopsurfaces (6) are of a cranked design.
 7. A robot according to claim 3,wherein either the upper arm (27) or the wrist joint (30) is providedwith means for locking the upper arm in hoisting position either on oneof the parallelogram arms (12) or the mounting head (11).
 8. A robotaccording to claim 1 wherein said guide means comprises guide shafts.